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><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="AUTH-PG-HBA-CONF"
>19.1. The <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> File</A
></H1
><P
>   Client authentication is controlled by a configuration file,
   which traditionally is named
   <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> and is stored in the database
   cluster's data directory.
   (<ACRONYM
CLASS="ACRONYM"
>HBA</ACRONYM
> stands for host-based authentication.) A default
   <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> file is installed when the data
   directory is initialized by <TT
CLASS="COMMAND"
>initdb</TT
>.  It is
   possible to place the authentication configuration file elsewhere,
   however; see the <A
HREF="runtime-config-file-locations.html#GUC-HBA-FILE"
>hba_file</A
> configuration parameter.
  </P
><P
>   The general format of the <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> file is
   a set of records, one per line. Blank lines are ignored, as is any
   text after the <TT
CLASS="LITERAL"
>#</TT
> comment character.
   Records cannot be continued across lines.
   A record is made
   up of a number of fields which are separated by spaces and/or tabs.
   Fields can contain white space if the field value is quoted.
   Quoting one of the keywords in a database, user, or address field (e.g.,
   <TT
CLASS="LITERAL"
>all</TT
> or <TT
CLASS="LITERAL"
>replication</TT
>) makes the word lose its special
   character, and just match a database, user, or host with that name.
  </P
><P
>   Each record specifies a connection type, a client IP address range
   (if relevant for the connection type), a database name, a user name,
   and the authentication method to be used for connections matching
   these parameters. The first record with a matching connection type,
   client address, requested database, and user name is used to perform
   authentication. There is no <SPAN
CLASS="QUOTE"
>"fall-through"</SPAN
> or
   <SPAN
CLASS="QUOTE"
>"backup"</SPAN
>: if one record is chosen and the authentication
   fails, subsequent records are not considered. If no record matches,
   access is denied.
  </P
><P
>   A record can have one of the seven formats
</P><PRE
CLASS="SYNOPSIS"
>local      <TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
>  [<SPAN
CLASS="OPTIONAL"
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></SPAN
>]
host       <TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>address</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
>  [<SPAN
CLASS="OPTIONAL"
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></SPAN
>]
hostssl    <TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>address</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
>  [<SPAN
CLASS="OPTIONAL"
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></SPAN
>]
hostnossl  <TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>address</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
>  [<SPAN
CLASS="OPTIONAL"
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></SPAN
>]
host       <TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>IP-address</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>IP-mask</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
>  [<SPAN
CLASS="OPTIONAL"
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></SPAN
>]
hostssl    <TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>IP-address</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>IP-mask</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
>  [<SPAN
CLASS="OPTIONAL"
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></SPAN
>]
hostnossl  <TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>IP-address</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>IP-mask</I
></TT
>  <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
>  [<SPAN
CLASS="OPTIONAL"
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></SPAN
>]</PRE
><P>
   The meaning of the fields is as follows:

   <P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="LITERAL"
>local</TT
></DT
><DD
><P
>       This record matches connection attempts using Unix-domain
       sockets.  Without a record of this type, Unix-domain socket
       connections are disallowed.
      </P
></DD
><DT
><TT
CLASS="LITERAL"
>host</TT
></DT
><DD
><P
>       This record matches connection attempts made using TCP/IP.
       <TT
CLASS="LITERAL"
>host</TT
> records match either
       <ACRONYM
CLASS="ACRONYM"
>SSL</ACRONYM
> or non-<ACRONYM
CLASS="ACRONYM"
>SSL</ACRONYM
> connection
       attempts.
      </P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>       Remote TCP/IP connections will not be possible unless
       the server is started with an appropriate value for the
       <A
HREF="runtime-config-connection.html#GUC-LISTEN-ADDRESSES"
>listen_addresses</A
> configuration parameter,
       since the default behavior is to listen for TCP/IP connections
       only on the local loopback address <TT
CLASS="LITERAL"
>localhost</TT
>.
      </P
></BLOCKQUOTE
></DIV
></DD
><DT
><TT
CLASS="LITERAL"
>hostssl</TT
></DT
><DD
><P
>       This record matches connection attempts made using TCP/IP,
       but only when the connection is made with <ACRONYM
CLASS="ACRONYM"
>SSL</ACRONYM
>
       encryption.
      </P
><P
>       To make use of this option the server must be built with
       <ACRONYM
CLASS="ACRONYM"
>SSL</ACRONYM
> support. Furthermore,
       <ACRONYM
CLASS="ACRONYM"
>SSL</ACRONYM
> must be enabled at server start time
       by setting the <A
HREF="runtime-config-connection.html#GUC-SSL"
>ssl</A
> configuration parameter (see
       <A
HREF="ssl-tcp.html"
>Section 17.9</A
> for more information).
      </P
></DD
><DT
><TT
CLASS="LITERAL"
>hostnossl</TT
></DT
><DD
><P
>       This record type has the opposite behavior of <TT
CLASS="LITERAL"
>hostssl</TT
>;
       it only matches connection attempts made over
       TCP/IP that do not use <ACRONYM
CLASS="ACRONYM"
>SSL</ACRONYM
>.
      </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>database</I
></TT
></DT
><DD
><P
>       Specifies which database name(s) this record matches.  The value
       <TT
CLASS="LITERAL"
>all</TT
> specifies that it matches all databases.
       The value <TT
CLASS="LITERAL"
>sameuser</TT
> specifies that the record
       matches if the requested database has the same name as the
       requested user.  The value <TT
CLASS="LITERAL"
>samerole</TT
> specifies that
       the requested user must be a member of the role with the same
       name as the requested database.  (<TT
CLASS="LITERAL"
>samegroup</TT
> is an
       obsolete but still accepted spelling of <TT
CLASS="LITERAL"
>samerole</TT
>.)
       The value <TT
CLASS="LITERAL"
>replication</TT
> specifies that the record
       matches if a replication connection is requested (note that
       replication connections do not specify any particular database).
       Otherwise, this is the name of
       a specific <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> database.
       Multiple database names can be supplied by separating them with
       commas.  A separate file containing database names can be specified by
       preceding the file name with <TT
CLASS="LITERAL"
>@</TT
>.
      </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>user</I
></TT
></DT
><DD
><P
>       Specifies which database user name(s) this record
       matches. The value <TT
CLASS="LITERAL"
>all</TT
> specifies that it
       matches all users.  Otherwise, this is either the name of a specific
       database user, or a group name preceded by <TT
CLASS="LITERAL"
>+</TT
>.
       (Recall that there is no real distinction between users and groups
       in <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>; a <TT
CLASS="LITERAL"
>+</TT
> mark really means
       <SPAN
CLASS="QUOTE"
>"match any of the roles that are directly or indirectly members
       of this role"</SPAN
>, while a name without a <TT
CLASS="LITERAL"
>+</TT
> mark matches
       only that specific role.)
       Multiple user names can be supplied by separating them with commas.
       A separate file containing user names can be specified by preceding the
       file name with <TT
CLASS="LITERAL"
>@</TT
>.
      </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>address</I
></TT
></DT
><DD
><P
>       Specifies the client machine addresses that this record
       matches.  This field can contain either a host name, an IP
       address range, or one of the special key words mentioned below.
      </P
><P
>       An IP address is specified in standard dotted decimal
       notation with a <ACRONYM
CLASS="ACRONYM"
>CIDR</ACRONYM
> mask length.  The mask
       length indicates the number of high-order bits of the client
       IP address that must match.  Bits to the right of this should
       be zero in the given IP address.
       There must not be any white space between the IP address, the
       <TT
CLASS="LITERAL"
>/</TT
>, and the CIDR mask length.
      </P
><P
>       Typical examples of an IP address range specified this way are
       <TT
CLASS="LITERAL"
>172.20.143.89/32</TT
> for a single host, or
       <TT
CLASS="LITERAL"
>172.20.143.0/24</TT
> for a small network, or
       <TT
CLASS="LITERAL"
>10.6.0.0/16</TT
> for a larger one.
       <TT
CLASS="LITERAL"
>0.0.0.0/0</TT
> represents all
       IPv4 addresses, and <TT
CLASS="LITERAL"
>::/0</TT
> represents
       all IPv6 addresses.
       To specify a single host, use a CIDR mask of 32 for IPv4 or
       128 for IPv6.  In a network address, do not omit trailing zeroes.
      </P
><P
>       An IP address given in IPv4 format will match IPv6 connections that
       have the corresponding address, for example <TT
CLASS="LITERAL"
>127.0.0.1</TT
>
       will match the IPv6 address <TT
CLASS="LITERAL"
>::ffff:127.0.0.1</TT
>.  An entry
       given in IPv6 format will match only IPv6 connections, even if the
       represented address is in the IPv4-in-IPv6 range.  Note that entries
       in IPv6 format will be rejected if the system's C library does not have
       support for IPv6 addresses.
      </P
><P
>       You can also write <TT
CLASS="LITERAL"
>all</TT
> to match any IP address,
       <TT
CLASS="LITERAL"
>samehost</TT
> to match any of the server's own IP
       addresses, or <TT
CLASS="LITERAL"
>samenet</TT
> to match any address in any
       subnet that the server is directly connected to.
      </P
><P
>       If a host name is specified (anything that is not an IP address
       or a special key word is processed as a potential host name),
       that name is compared with the result of a reverse name
       resolution of the client's IP address (e.g., reverse DNS
       lookup, if DNS is used).  Host name comparisons are case
       insensitive.  If there is a match, then a forward name
       resolution (e.g., forward DNS lookup) is performed on the host
       name to check whether any of the addresses it resolves to are
       equal to the client's IP address.  If both directions match,
       then the entry is considered to match.  (The host name that is
       used in <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> should be the one that
       address-to-name resolution of the client's IP address returns,
       otherwise the line won't be matched.  Some host name databases
       allow associating an IP address with multiple host names, but
       the operating system will only return one host name when asked
       to resolve an IP address.)
      </P
><P
>       A host name specification that starts with a dot
       (<TT
CLASS="LITERAL"
>.</TT
>) matches a suffix of the actual host
       name.  So <TT
CLASS="LITERAL"
>.example.com</TT
> would match
       <TT
CLASS="LITERAL"
>foo.example.com</TT
> (but not just
       <TT
CLASS="LITERAL"
>example.com</TT
>).
      </P
><P
>       When host names are specified
       in <TT
CLASS="FILENAME"
>pg_hba.conf</TT
>, you should make sure that
       name resolution is reasonably fast.  It can be of advantage to
       set up a local name resolution cache such
       as <TT
CLASS="COMMAND"
>nscd</TT
>.  Also, you may wish to enable the
       configuration parameter <TT
CLASS="VARNAME"
>log_hostname</TT
> to see
       the client's host name instead of the IP address in the log.
      </P
><TABLE
CLASS="SIDEBAR"
BORDER="1"
CELLPADDING="5"
><TR
><TD
><DIV
CLASS="SIDEBAR"
><P
></P
><A
NAME="AEN30197"
></A
><P
>        Occasionally, users have wondered why host names are handled
        in this seemingly complicated way with two name resolutions
        and requiring reverse lookup of IP addresses, which is
        sometimes not set up or points to some undesirable host name.
        It is primarily for efficiency: A connection attempt requires
        two resolver lookups of the current client's address.  If
        there is resolver problem with that address, it becomes only
        that client's problem.  A hypothetical alternative
        implementation which only does forward lookups would have to
        resolve every host name mentioned in
        <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> at every connection attempt.
        That would already be slow by itself.  And if there is a
        resolver problem with one of the host names, it becomes
        everyone's problem.
       </P
><P
>        Also, a reverse lookup is necessary to implement the suffix
        matching feature, because the actual client host name needs to
        be known in order to match it against the pattern.
       </P
><P
>        Note that this behavior is consistent with other popular
        implementations of host name-based access control, such as the
        Apache HTTP Server and TCP Wrappers.
       </P
><P
></P
></DIV
></TD
></TR
></TABLE
><P
>       This field only applies to <TT
CLASS="LITERAL"
>host</TT
>,
       <TT
CLASS="LITERAL"
>hostssl</TT
>, and <TT
CLASS="LITERAL"
>hostnossl</TT
> records.
      </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>IP-address</I
></TT
><BR><TT
CLASS="REPLACEABLE"
><I
>IP-mask</I
></TT
></DT
><DD
><P
>       These fields can be used as an alternative to the
       <TT
CLASS="REPLACEABLE"
><I
>CIDR-address</I
></TT
> notation. Instead of
       specifying the mask length, the actual mask is specified in a
       separate column. For example, <TT
CLASS="LITERAL"
>255.0.0.0</TT
> represents an IPv4
       CIDR mask length of 8, and <TT
CLASS="LITERAL"
>255.255.255.255</TT
> represents a
       CIDR mask length of 32.
      </P
><P
>       These fields only apply to <TT
CLASS="LITERAL"
>host</TT
>,
       <TT
CLASS="LITERAL"
>hostssl</TT
>, and <TT
CLASS="LITERAL"
>hostnossl</TT
> records.
      </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
></DT
><DD
><P
>       Specifies the authentication method to use when a connection matches
       this record. The possible choices are summarized here; details
       are in <A
HREF="auth-methods.html"
>Section 19.3</A
>.

       <P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="LITERAL"
>trust</TT
></DT
><DD
><P
>          Allow the connection unconditionally. This method
          allows anyone that can connect to the
          <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> database server to login as
          any <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> user they wish,
          without the need for a password or any other authentication.  See <A
HREF="auth-methods.html#AUTH-TRUST"
>Section 19.3.1</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>reject</TT
></DT
><DD
><P
>          Reject the connection unconditionally. This is useful for
          <SPAN
CLASS="QUOTE"
>"filtering out"</SPAN
> certain hosts from a group, for example a
          <TT
CLASS="LITERAL"
>reject</TT
> line could block a specific host from connecting,
          while a later line allows the remaining hosts in a specific
          network to connect.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>md5</TT
></DT
><DD
><P
>          Require the client to supply an MD5-encrypted password for
          authentication.
          See <A
HREF="auth-methods.html#AUTH-PASSWORD"
>Section 19.3.2</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>password</TT
></DT
><DD
><P
>          Require the client to supply an unencrypted password for
          authentication.
          Since the password is sent in clear text over the
          network, this should not be used on untrusted networks.
          See <A
HREF="auth-methods.html#AUTH-PASSWORD"
>Section 19.3.2</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>gss</TT
></DT
><DD
><P
>          Use GSSAPI to authenticate the user. This is only
          available for TCP/IP connections. See <A
HREF="auth-methods.html#GSSAPI-AUTH"
>Section 19.3.3</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>sspi</TT
></DT
><DD
><P
>          Use SSPI to authenticate the user. This is only
          available on Windows. See <A
HREF="auth-methods.html#SSPI-AUTH"
>Section 19.3.4</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>krb5</TT
></DT
><DD
><P
>          Use Kerberos V5 to authenticate the user. This is only
          available for TCP/IP connections.  See <A
HREF="auth-methods.html#KERBEROS-AUTH"
>Section 19.3.5</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>ident</TT
></DT
><DD
><P
>          Obtain the operating system user name of the client
          by contacting the ident server on the client
          and check if it matches the requested database user name.
          Ident authentication can only be used on TCP/IP
          connections. When specified for local connections, peer
          authentication will be used instead.
          See <A
HREF="auth-methods.html#AUTH-IDENT"
>Section 19.3.6</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>peer</TT
></DT
><DD
><P
>          Obtain the client's operating system user name from the operating
          system and check if it matches the requested database user name.
          This is only available for local connections.
          See <A
HREF="auth-methods.html#AUTH-PEER"
>Section 19.3.7</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>ldap</TT
></DT
><DD
><P
>          Authenticate using an <ACRONYM
CLASS="ACRONYM"
>LDAP</ACRONYM
> server. See <A
HREF="auth-methods.html#AUTH-LDAP"
>Section 19.3.8</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>radius</TT
></DT
><DD
><P
>          Authenticate using a RADIUS server. See <A
HREF="auth-methods.html#AUTH-RADIUS"
>Section 19.3.9</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>cert</TT
></DT
><DD
><P
>          Authenticate using SSL client certificates. See
          <A
HREF="auth-methods.html#AUTH-CERT"
>Section 19.3.10</A
> for details.
         </P
></DD
><DT
><TT
CLASS="LITERAL"
>pam</TT
></DT
><DD
><P
>          Authenticate using the Pluggable Authentication Modules
          (PAM) service provided by the operating system.  See <A
HREF="auth-methods.html#AUTH-PAM"
>Section 19.3.11</A
> for details.
         </P
></DD
></DL
></DIV
><P>

      </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>auth-options</I
></TT
></DT
><DD
><P
>       After the <TT
CLASS="REPLACEABLE"
><I
>auth-method</I
></TT
> field, there can be field(s) of
       the form <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
><TT
CLASS="LITERAL"
>=</TT
><TT
CLASS="REPLACEABLE"
><I
>value</I
></TT
> that
       specify options for the authentication method. Details about which
       options are available for which authentication methods appear below.
      </P
></DD
></DL
></DIV
><P>
  </P
><P
>   Files included by <TT
CLASS="LITERAL"
>@</TT
> constructs are read as lists of names,
   which can be separated by either whitespace or commas.  Comments are
   introduced by <TT
CLASS="LITERAL"
>#</TT
>, just as in
   <TT
CLASS="FILENAME"
>pg_hba.conf</TT
>, and nested <TT
CLASS="LITERAL"
>@</TT
> constructs are
   allowed.  Unless the file name following <TT
CLASS="LITERAL"
>@</TT
> is an absolute
   path, it is taken to be relative to the directory containing the
   referencing file.
  </P
><P
>   Since the <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> records are examined
   sequentially for each connection attempt, the order of the records is
   significant. Typically, earlier records will have tight connection
   match parameters and weaker authentication methods, while later
   records will have looser match parameters and stronger authentication
   methods. For example, one might wish to use <TT
CLASS="LITERAL"
>trust</TT
>
   authentication for local TCP/IP connections but require a password for
   remote TCP/IP connections. In this case a record specifying
   <TT
CLASS="LITERAL"
>trust</TT
> authentication for connections from 127.0.0.1 would
   appear before a record specifying password authentication for a wider
   range of allowed client IP addresses.
  </P
><P
>   The <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> file is read on start-up and when
   the main server process receives a
   <SPAN
CLASS="SYSTEMITEM"
>SIGHUP</SPAN
>
   signal. If you edit the file on an
   active system, you will need to signal the postmaster
   (using <TT
CLASS="LITERAL"
>pg_ctl reload</TT
> or <TT
CLASS="LITERAL"
>kill -HUP</TT
>) to make it
   re-read the file.
  </P
><DIV
CLASS="TIP"
><BLOCKQUOTE
CLASS="TIP"
><P
><B
>Tip: </B
>    To connect to a particular database, a user must not only pass the
    <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> checks, but must have the
    <TT
CLASS="LITERAL"
>CONNECT</TT
> privilege for the database.  If you wish to
    restrict which users can connect to which databases, it's usually
    easier to control this by granting/revoking <TT
CLASS="LITERAL"
>CONNECT</TT
> privilege
    than to put the rules in <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> entries.
   </P
></BLOCKQUOTE
></DIV
><P
>   Some examples of <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> entries are shown in
   <A
HREF="auth-pg-hba-conf.html#EXAMPLE-PG-HBA.CONF"
>Example 19-1</A
>. See the next section for details on the
   different authentication methods.
  </P
><DIV
CLASS="EXAMPLE"
><A
NAME="EXAMPLE-PG-HBA.CONF"
></A
><P
><B
>Example 19-1. Example <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> Entries</B
></P
><PRE
CLASS="PROGRAMLISTING"
># Allow any user on the local system to connect to any database with
# any database user name using Unix-domain sockets (the default for local
# connections).
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
local   all             all                                     trust

# The same using local loopback TCP/IP connections.
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             127.0.0.1/32            trust

# The same as the previous line, but using a separate netmask column
#
# TYPE  DATABASE        USER            IP-ADDRESS      IP-MASK             METHOD
host    all             all             127.0.0.1       255.255.255.255     trust

# The same over IPv6.
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             ::1/128                 trust

# The same using a host name (would typically cover both IPv4 and IPv6).
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             localhost               trust

# Allow any user from any host with IP address 192.168.93.x to connect
# to database "postgres" as the same user name that ident reports for
# the connection (typically the operating system user name).
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    postgres        all             192.168.93.0/24         ident

# Allow any user from host 192.168.12.10 to connect to database
# "postgres" if the user's password is correctly supplied.
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    postgres        all             192.168.12.10/32        md5

# Allow any user from hosts in the example.com domain to connect to
# any database if the user's password is correctly supplied.
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             .example.com            md5

# In the absence of preceding "host" lines, these two lines will
# reject all connections from 192.168.54.1 (since that entry will be
# matched first), but allow Kerberos 5 connections from anywhere else
# on the Internet.  The zero mask causes no bits of the host IP
# address to be considered, so it matches any host.
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             192.168.54.1/32         reject
host    all             all             0.0.0.0/0               krb5

# Allow users from 192.168.x.x hosts to connect to any database, if
# they pass the ident check.  If, for example, ident says the user is
# "bryanh" and he requests to connect as PostgreSQL user "guest1", the
# connection is allowed if there is an entry in pg_ident.conf for map
# "omicron" that says "bryanh" is allowed to connect as "guest1".
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             192.168.0.0/16          ident map=omicron

# If these are the only three lines for local connections, they will
# allow local users to connect only to their own databases (databases
# with the same name as their database user name) except for administrators
# and members of role "support", who can connect to all databases.  The file
# $PGDATA/admins contains a list of names of administrators.  Passwords
# are required in all cases.
#
# TYPE  DATABASE        USER            ADDRESS                 METHOD
local   sameuser        all                                     md5
local   all             @admins                                 md5
local   all             +support                                md5

# The last two lines above can be combined into a single line:
local   all             @admins,+support                        md5

# The database column can also use lists and file names:
local   db1,db2,@demodbs  all                                   md5</PRE
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